Submersible Vessels

ABSTRACT

A submarine has a pressure hull  20  which includes a number of adjoining transparent viewing sections  21  and  22  in the shape of truncated spheres. The sections  21  and  22  are clamped to a body section  23, 24  by a cage  40  and tension rods  44  which pass slidably through a thrust ring  38  interposed between the transparent sections. Access to a passenger compartment within the pressure hull is obtained via a hatch  32  in a mid section  23 . The pressure hull is housed in an external hull designed for surface cruising. Ballast tanks are formed between pressure hull and the external hull, and the tie rods pass through low pressure seals to pivotal anchorage points within the ballast tanks.

TECHNICAL FIELD OF THE INVENTION

This invention relates to submersible vessels such as (without prejudiceto the generality) submarines.

BACKGROUND

It has long been known that hollow submersible bodies of spherical shapeare capable of withstanding approximately twice the external pressure ofa substantially cylindrical body of comparable diameter and wallthickness. Submersible vessels having pressure hulls formed from anumber of interconnected sections in the form of truncated spheres arealready known, as disclosed for example in GB 279 483, GB 2 223 716 Aand U.S. Pat. No. 5,477,798.

In submersible vessels, windows or viewports may also be formed with apart-spherical shape for strength. A common material used in themanufacture of such viewports is acrylic plastics, since this has arefractive index close to that of seawater and therefore minimisesvisual distortion. However, the viewport mounting must be capable ofmaintaining an effective seal over a wide range of external pressuresand operating temperatures.

In a known form of mounting for part-spherical viewports, a radial faceof the viewport surrounding a circular opening is seated against apart-conical surface with provision of suitable seals. The viewport isheld in position by a clamping ring which holds a peripheral edge of theviewport against the part-conical seat. Such arrangements may be used toeffectively secure viewports of substantial size.

In general, increasing the angle of the opening reduces the range ofhydrostatic pressures which the mounting can handle. On the other hand,reducing the angle of the opening restricts the internal space. Inpressure hulls which include a viewing area formed from a number ofadjoining part-spherical transparent sections this would place arestriction on the size of the internal compartment.

The present invention seeks to provide a new and inventive form ofsubmersible vessel having a number of adjacent part-sphericaltransparent sections in which the size of the internal compartment ismaximised whilst maintaining an effective seal throughout a wide rangeof external pressures.

SUMMARY OF THE INVENTION

The present invention provides a submersible vessel having a pressurehull which includes:

-   -   a body section,    -   a substantially transparent part-spherical end section having a        single opening, and    -   at least one substantially transparent part-spherical        intermediate section having a pair of openings and being        disposed between the end section and the body section such that        the said sections provide a common internal compartment;    -   characterised by    -   a cage partially surrounding the end section;    -   and    -   a plurality of tension elements connecting the cage to the body        section, disposed externally of the intermediate section or        sections.

The cage preferably comprises a tension ring and a plurality ofanchoring members projecting from the tension ring and each connectedwith a respective tension element.

In a preferred arrangement a thrust member is interposed betweenadjacent transparent sections, and the tension elements pass slidablythrough the thrust member. The thrust member may thus locate the tensionelements whilst balancing the sealing pressures on opposite sides of thethrust member.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred totherein are included by way of non-limiting example in order toillustrate how the invention may be put into practice. In the drawings:

FIG. 1 is an external side view of a submarine in accordance with theinvention;

FIG. 2 is a plan view of the submarine;

FIG. 3 is an end view of the submarine as seen from the bow end;

FIG. 4 is a side view of an internal pressure hull of the submarine;

FIG. 5 is a plan view of the pressure hull which comprises a bodysection and two transparent sections;

FIG. 6 is an end view of the pressure hull as seen from the bow end;

FIG. 7 is a transverse section through the pressure hull, the right handside of the drawing showing the section A-A of FIG. 4 and the left handside showing the section B-B;

FIG. 8 is a section through the area of the thrust ring which separatesthe two transparent sections, including an inset detail; and

FIG. 9 is a section through the area where the transparent sections jointhe body section.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 3 show a vessel which is commonly referred to as a submarine.The vessel is capable of both surface and sub-surface use. The vesselhas an external hull 10 which is shaped for surface cruising, having aleading bow end 11 and an aft end 12 with a propeller 15. During surfaceuse the propeller 15 may be driven by an internal diesel engine toprovide economical use over a considerable distance, but during divesthe propeller may be driven by an internal electric motor powered by arechargeable battery. The external hull is surmounted by a deck area 16,which is surrounded by an upstanding safety wall 17. The bow end 11 isprovided with a transparent window 18 which extends on both sides of thevessel.

The external hull 10 contains an internal pressure hull 20, shown inFIGS. 4 to 7, which is designed to withstand the high external pressuresencountered during sub-surface dives. Starting at the bow end, thepressure hull includes a bow section 21, an intermediate section 22, amid section 23, and an aft section 24. The bow and intermediate sections21 and 22 are both formed of transparent acrylic plastics (othersuitable transparent materials could be used, of course) whereas the midand aft sections 23 and 24 form a metal body section, both beinggenerally of cylindrical shape with circumferential, axially-spacedreinforcing rings 25. The aft section 24 is closed by a part-sphericalend 26 and is joined to the mid section 23 by conventional flange seals27. Referring back to FIG. 1, the transparent sections 21 and 22 formpart of an internal passenger compartment 30 within the pressure hull,which extends into the mid and aft sections. The passenger compartmentis accessed through a cylindrical access hatch 32 which passes throughthe top of the mid section 23 into the deck area 16 and is closed duringdives by a pressure cover 33. The remainder of the body section 23, 24outside the passenger compartment contains service equipment such as thedrive motors, batteries, air supply equipment etc.

A space is formed between the body section 23, 24 of the pressure hulland the external hull 10, containing one or more enclosed ballast tankswhich are part-flooded to control the diving depth. The transparentsections 21 and 22 of the pressure hull are disposed behind the bowwindow 18 so that the external environment is clearly visible to peoplein the passenger compartment. The intervening space between the sections21, 22 and the window 18 may be flooded to reduce pressure forces on thewindow 18 during dives.

Returning to FIGS. 4 to 7, the bow section 21 is formed as a truncatedsphere with a single opening subtending an angle C at the centre of thesphere of about 120°. The intermediate section 22 is similarly formed asa truncated sphere of the same radius, but this section has two opposingopenings each subtending the same angle (about 120 degrees) from thecentre of the sphere. A metal thrust ring 38 is interposed between thetransparent sections 21 and 22 whereas the mid section 23 is providedwith a ring-shaped seat 39 against which the intermediate section 22 isheld. A cage 40 is shaped to partially surround the bow section 21, incontact with its external surface. The cage includes a tension ring 41and a number of anchoring members 42 which project aft from the tensionring, each terminating, adjacent to the thrust ring 38, in a pair ofspaced pivot plates 43. A respective tension rod 44 is pivotallyconnected with each of the anchoring members by means of a pivot pininserted through the plates 43. The tension rods 44 extend externally ofthe intermediate section 22 substantially parallel to the fore-aft axisof the pressure hull, each terminating in a clevis 45. Each of thetension rods 44 is pivotally secured to the mid section 23 by means of arespective external anchorage plate 46. The two uppermost tension rodsare secured to circumferential anchorage plates on the access hatch 32whereas the remaining plates 46 project radially from the mid section.The anchorage plates 46 are all located within the ballast tanks, butthe tie rods pass slidably through low pressure seals at the point ofentry 47 into the ballast tanks.

The cage 40 and tension rods 44 clamp the transparent sections 21 and 22to the mid section 23. Eight tension rods are provided in the presentembodiment. However four of the rods are disposed at the upper region ofthe transparent sections 21 and 22 and four are disposed at the lowerregion. The rods 44 do not therefore impede the side view from thepassenger compartment but the balanced arrangement enables the cage 40to apply even clamping pressure to the transparent sections. It willalso be noted that a base platform 48 projects forwardly from the midsection 23 below the transparent sections 21 and 22, which supports thetransparent sections during assembly and maintenance of the pressurehull.

The thrust ring 38 is provided with outwardly-projecting flanges 49through which the tension rods 44 are slidably inserted to ensureaccurate circumferential and radial location of the rods. FIG. 8 showshow the thrust ring 38 is interposed between the two transparentsections 21 and 22 whilst FIG. 9 shows how the intermediate section 22is held against the seat 39 of the mid section 23. The adjacent openingof each section is surrounded by a radially-extending face 50 which issupported against a respective part-conical seat 51. The outercircumferential limit of each seat is formed by an abutment face 53which projects substantially perpendicularly from the seat 51. (Seeinset detail of FIG. 8.) The adjacent corner of the transparent section,between the radially-extending face 50 and the external face 54, isformed with a short inclined face 55. An O-ring seal 56 is enclosedbetween the seat 51, the abutment face 53 and the inclined face 55 sothat, when the rods 44 are correctly tensioned, the O-rings aresealingly compressed between these three faces.

During a dive the hydrostatic pressures on the external faces of thetransparent sections are resisted by the cage 40 and tension rods 44 sothat the radial faces 50 are held against the part-conical seats 51.Since the thrust ring 38 is slidably located on the tension rods 44 thecompression forces are equally divided between the three seats 51. Asthe external pressure increases the faces 50 may eventually slideradially inwards on the seats 51 but as long as the O-rings remaincompressed an effective pressure seal is maintained.

In larger vessels which are intended to accommodate a larger number ofpassengers the pressure hull may include two or more intermediatesections 22 with a similar thrust ring 38 interposed between eachadjacent pair of sections.

With the arrangement described the size of the passenger compartment ismaximised whilst maintaining effective seals over a wider range ofexternal hydrostatic pressures. The high pressures to which the sealsmay be subjected during a dive remain substantially balanced throughoutthe intended operating range.

It will be appreciated that the features disclosed herein may be presentin any feasible combination. Whilst the above description lays emphasison those areas which, in combination, are believed to be new, protectionis claimed for any inventive combination of the features disclosedherein.

1. A submersible vessel having a pressure hull which includes: a bodysection (23, 24), a substantially transparent part-spherical end section(21) having a single opening, and at least one substantially transparentpart-spherical intermediate section (22) having a pair of openings andbeing disposed between the end section (21) and the body section (23,24), the transparent sections forming part of a common passengercompartment (30); characterised by a cage (40) partially surrounding theend section (21), and a plurality of tension elements (44) connectingthe cage to the body section (23, 24), disposed externally of theintermediate section or sections (22).
 2. A submersible vessel accordingto claim 1 in which the cage (40) comprises a tension ring (41) and aplurality of anchoring elements (42) projecting from the tension ringfor connection with a respective tension element (44).
 3. A submersiblevessel according to claim 2 in which the tension elements (44) arepivotally connected with the anchoring elements (42).
 4. A submersiblevessel according to claim 1 in which a thrust member (38) is interposedbetween the end section (21) and the adjacent intermediate section (22).5. A submersible vessel according to claim 4 in which the tensionelements (44) pass slidably through the thrust member (38).
 6. Asubmersible vessel according to claim 1 in which the tension elements(44) are anchored to the body section (23, 24).
 7. A submersible vesselaccording to claim 6 in which the tension elements (44) are anchored tothe body section (23, 24) by pivotal connections.
 8. A submersiblevessel according to claim 1 in which the body section (23, 24) of thepressure hull is provided with external ballast tanks.
 9. A submersiblevessel according to claim 8 in which the tension elements (44) extendsealably (47) into the ballast tanks.
 10. A submersible vessel accordingto claim 1 in which the tension elements (44) are arranged in two groupsdisposed at top and bottom regions of the transparent sections (21, 22).11. A submersible vessel according to claim 10 in which both groups havethe same number of tension elements (44).